This invention relates to a ball endmill, particularly to a ball endmill provided with an arcuate cutting edge and able to perform an effective cutting.
Various ball endmills are known, one of which is disclosed in U.S. Pat. No. 3,409,965. The ball endmill according to the U.S. patent comprises a cylindrical body and a U-shaped tip made of a cemented carbide and brazed to the cylindrical body. Such a known ball endmill proves effective in cutting a shallow groove or hole in a workpiece.
Ball endmills are used generally to cut metal moulds, automatically controlled by a program recorded on a tape. The cutting conditions are changing, and often the ball endmills are so operated as to cut a deep groove or hole in the workpiece. The ball endmills should therefore be so designed as to achieve a deep cutting as well as a shallow cutting. In designing a ball endmill which can effect both shallow and deep cuttings, it is necessary to take into consideration the shape of a cutting edge, the mechanical strength of a cutter, the removal of chips and other factors. In short, an improved ball endmill which can cut a workpiece smoothly despite ever-changing cutting conditions is desired very much today.